There are numerous definitions of fitness today but one that has stood the test of time was that proposed by Aristotle around about 2,500 years ago. He put it quite simply when he said that something that is well suited to its purpose is fit. If we look at the human body and examine its skeleton, muscles, lungs, cardiovascular system and endocrine system I think it is fair to say that it is suited to its purpose.
However, while the human body may be well suited to its purpose and therefore fit, it will only stay that way with regular exercise for each and every one of its component parts.
For example, physical activity causes your heart to work harder, increasing blood flow which both floods the body with fresh oxygen and removes waste products.
Similarly, exercise increases your lung capacity so that it can draw in extra oxygen to bathe the tissues and help power the heart. Greater lung capacity also means greater exhalation to remove harmful carbon dioxide, which is a waste product of certain chemical reactions within the body.
Regular, exercise helps to increase High-Density Lipoprotein (HDL) cholesterol (which is one 'good' form of cholesterol. It also helps to regulate blood sugar levels and converts stored fat into sugars that are used to provide energy. This process helps to prevent obesity and is important in the control of such conditions as diabetes.
All of these benefits, while very real, are also largely unseen but other benefits of a regular fitness program are more obvious and include an increased muscle mass, toned legs, arms, stomach, buttocks, and a generally healthier looking skin. At the same time exercise provides greater strength, improved balance, higher endurance and, more often than not, a better mental outlook on life.
Of course different forms of exercise routine will concentrate on different areas of the body. Aerobic routines will help the cardiovascular and pulmonary systems, weight training builds muscle tone and mass, pilates and yoga aid balance, flexibility and muscular control. But, while each of these may focus on particular areas, they all help to improve fitness throughout the body, since the various systems of the body are all inter-connected.
Best of all, these benefits, at least to some extent, can be achieved with a minimum of daily effort. Moderately intense activity for as little as 20 to 30 minutes each day, five days a week, will go a long way toward improving your overall fitness.
A number of simple activities which provide excellent exercise can be performed without the need for any special training or equipment. These might include a brisk walk, a short daily jog or even simply taking the stairs rather than the elevator.
More vigorous activity such as playing tennis, a few laps in the swimming pool, an hour on the treadmill or exercise bike, or any of a dozen other activities, can increase your fitness considerably with only a small investment of time and money.
For those who are really committed to achieving a high level of fitness then there are numerous gym available and just about every kind of home fitness equipment imaginable can be purchased today at prices to fit all budgets.